Yes, the option was closed for a long time due to some happenings in past, but opened for edit again not too long ago.
But I also seem to remember it is just for a period after you've published a post, but for how many hours or what period the edit button is active, I don't remember.
However, the button is not visible until you have clicked 'submit' and then go back to your post again.

Edit: Put in picture illustration edit: